One of the most curious of Mexico’s dozens of indigenous languages is the whistled language of one group of the Chinantec people who live in the state of Oaxaca. This group’s conventional spoken language is complemented by a language based entirely on whistles. Only a few people remain who speak this whistled language fluently. The language is whistled primarily by men (and much less fluently by children); female members of the group understand it but do not use it.

It is thought that whistled languages developed to enable communication between isolated settlements in areas that were too remote for conventional spoken languages to be effective. The Chinantec’s whistled language has three distinct subsets, designed to be used over different distances. The loudest enables effective communication over a distance of around 200 meters (650 ft).

The Chinantec whistled language is now largely confined to the mist- and fog-shrouded slopes of the eastern side of the Sierra Juárez in the northern part of Oaxaca state, a region of high rainfall totals and luxuriant vegetation.

This 27 minute documentary relates the field studies investigating the Chinantec whistling language conducted by Dr. Mark Sicoli, Assistant Professor of Linguistics at Georgetown University. The main center of population of speakers of the whistling language is San Pedro Sochiapam. Sicoli believes that the whistled language may become extinct in the next decade; he hopes that his work documenting the language may one day provide the basis for its reintroduction or restoration.

If you only have a few minutes to devote to this video, then look at the section around 16 minutes in, where in a controlled experiment, one experienced Chinantec whistler helps a friend “navigate” through a fictitious village. The men each have a copy of a made-up map of the village, but are out of sight and able to communicate only by whistling.

The astonishing whistled language of the Chinantec is yet another of Mexico’s many cultural wonders that currently appears to be headed for extinction.